According to this press release from Zend, the registration for this year's Zend PHP Conference has officially opened and speaker submissions were up four-hundred percent from previous years.

Zend anticipates its biggest ever conference due to growing interest in the practical use of PHP to develop cloud applications, which is reflected in the 400 percent increase in cloud-related submissions to this year’s Call for Papers. Strong interest in enterprise mobility, web automation and PHP advances are also reflected in this year’s content. ZendCon 2011 will offer keynotes by industry and enterprise IT leaders, in-depth technical sessions and tutorials, technology previews, vendor exhibits and networking opportunities. The event targets professional developers, IT/development managers, system administrators and business managers interested in PHP technologies and solutions for web, mobile and cloud.

The point out a few highlights of this year's even including topics like cloud infrastructure, RIAs, mobile devices, application architecture and best practices. There'll also be a preview of what's coming in Zend Framework 2.0 as related to its cloud integration functionality. You can learn more about the conference and get your tickets at ZendCon.com.